Ethynodiol diacetate (Luteonorm, Luto-Metrodiol, Metrodiol, Continuin, Femulen, norethindrol diacetate), the diacetate ester form of ethynodiol, is one of the first synthetic steroidal progestogens used as a contraceptive drug.

Physicochemical Properties

Molecular Formula	C₂₄H₃₂O₄
Molecular Weight	384.51
Exact Mass	384.23
CAS #	297-76-7
Related CAS #	1231-93-2;297-76-7 (diacetate);
PubChem CID	9270
Appearance	White to off-white solid powder
Density	1.1±0.1 g/cm3
Boiling Point	461.1±45.0 °C at 760 mmHg
Melting Point	128 - 131ºC
Flash Point	221.8±27.1 °C
Vapour Pressure	0.0±1.1 mmHg at 25°C
Index of Refraction	1.546
LogP	5.44
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	5
Heavy Atom Count	28
Complexity	758
Defined Atom Stereocenter Count	7
SMILES	CC(=O)O[C@H]1CC[C@@H]2[C@H]3CC[C@]4([C@H]([C@@H]3CCC2=C1)CC[C@]4(C#C)OC(=O)C)C
InChi Key	ONKUMRGIYFNPJW-KIEAKMPYSA-N
InChi Code	InChI=1S/C24H32O4/c1-5-24(28-16(3)26)13-11-22-21-8-6-17-14-18(27-15(2)25)7-9-19(17)20(21)10-12-23(22,24)4/h1,14,18-22H,6-13H2,2-4H3/t18-,19-,20+,21+,22-,23-,24-/m0/s1
Chemical Name	(3S,8R,9S,10R,13S,14S,17R)-17-ethynyl-13-methyl-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthrene-3,17-diyl diacetate
Synonyms	Luteonorm, Luto-Metrodiol, Metrodiol,Continuin, Femulen, norethindrol diacetate, ethynodiol diacetate
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	In vitro activity: Nordihydroguaiaretic acid (NDGA) (< 1.5 μM) decreases the percentage of sister chronnatid exchanges (SCEs) in human lymphocyte culture treated with ethynodiol diacetate (150 μg/mL). Since the NDGA treatment, in the presence of S9 mix, reduce the genotoxic damage by ethynodiol diacetate, the reduction may be due to the inhibition of cytochrome P450s which prevents the metabolic activation of ethynodiol diacetate or NDGA may act as a free radical scavenger. Ethynodiol diacetate (150 μg/mL) increases sister chromatid exchanges (SCEs) and chromosomal aberrations (CAs) frequencies and inhibits lymphocyte proliferation in the presence of S9 mix in human lymphocyte.
ln Vivo	Ethynodiol diacetate (6 mg/kg b.w. daily) significantly increases the amounts of excreted 3alpha-hydroxy-5alpha-pregnan-20-one and A-homo-3-oxa-5alpha-pregnane-4,20-dione in urine in female rats. Significant increase in the weights of pituitary, liver and kidneys are noted in rats treated with ethynodiol diacetate (6 mg/kg b.w. daily). Norgestrel (75 μg/day) and ethynodiol diacetate (150 μg/day), co-administered with ethinyl estradiol (7.5 μg/day), lowers the plasma concentrations of HDL cholesterol in cynomolgus monkeys.
Animal Protocol	150 μg/day Monkeys
Toxicity/Toxicokinetics	Protein Binding 50-85%
References	J Environ Biol.2007 Apr;28(2):279-82;Endocr Regul.1998 Sep;32(3):125-131.
Additional Infomation	Ethynodiol diacetate is a steroid ester and a terminal acetylenic compound. It has a role as an estrogen receptor modulator, a contraceptive drug and a synthetic oral contraceptive. It is functionally related to an ethynodiol. A synthetic progestational hormone used alone or in combination with estrogens as an oral contraceptive. Although etynodiol or ethynodiol are sometimes used as a synonym for ethynodiol diacetate, what is usually being referred to is actually ethynodiol diacetate and not ethynodiol (which is a separate drug that has never been marketed, see [DB13866]). Ethynodiol Diacetate is the diacetate salt form of ethynodiol, a semi-synthetic progestational hormone agonist. Ethynodiol diacetate binds to cytoplasmic progesterone receptors in the reproductive system and subsequently activates progesterone receptor mediated gene expression. As a result of the negative feedback mechanism, luteinizing hormone (LH) release is inhibited, which leads to an inhibition of ovulation and an alteration in the cervical mucus and endometrium. In addition, ethynodiol diacetate has weak oestrogenic and androgenic properties. A synthetic progestational hormone used alone or in combination with estrogens as an oral contraceptive (CONTRACEPTIVES, ORAL). Drug Indication For the prevention of pregnancy in women who elect to use this product as a method of contraception. Mechanism of Action Binds to the progesterone and estrogen receptors. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Once bound to the receptor, progestins like Ethynodiol Diacetate will slow the frequency of release of gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt the pre-ovulatory LH (luteinizing hormone) surge. Pharmacodynamics Ethynodiol Diacetate is used as a female contraceptive. Ethynodiol Diacetate is a progestin or a synthetic form of the naturally occurring female sex hormone, progesterone. In a woman's normal menstrual cycle, an egg matures and is released from the ovaries (ovulation). The ovary then produces progesterone, preventing the release of further eggs and priming the lining of the womb for a possible pregnancy. If pregnancy occurs, progesterone levels in the body remain high, maintaining the womb lining. If pregnancy does not occur, progesterone levels in the body fall, resulting in a menstrual period. Ethynodiol Diacetate tricks the body processes into thinking that ovulation has already occurred, by maintaining high levels of the synthetic progesterone. This prevents the release of eggs from the ovaries.

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 39 mg/mL(101.43 mM) Ethanol: N/A H2O: N/A

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 3.75 mg/mL (9.75 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 37.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 3.75 mg/mL (9.75 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 37.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 3.75 mg/mL (9.75 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 37.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.6007 mL	13.0036 mL	26.0071 mL
	5 mM	0.5201 mL	2.6007 mL	5.2014 mL
	10 mM	0.2601 mL	1.3004 mL	2.6007 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.